title: High-order multiphoton fluorescence of organic molecules in solution by intense femtosecond laser pulses.
abstract: The five and possibly seven-photon fluorescence was observed for organic molecules in solution for the first time. A high-intensity laser enabled us to measure the properties of the high and any-order processes, and the emission could be directly visualized by the eye. These results showed that the common two-photon microscope could be upgraded to the higher order multiphoton microscope by choosing suitable excitation wavelengths. The multiphoton absorption cross sections differed by a factor of 10(33) as the order of the multiphoton process increased.
authors.affiliation: Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 Japan. tomo@sci.osaka-cu.ac.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yatsuhashi
authors.forename: Soh
authors.initials: S
authors.lastname: Ichikawa
authors.forename: Yukari
authors.initials: Y
authors.lastname: Shigematsu
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Nakashima